1. Field
The present disclosure relates generally to an RF transmitter. More specifically, the present disclosure relates to a tunable interface used between an RF transceiver integrated circuit (IC) chip and a plurality of narrowband power amplifiers (PAs).
2. Related Art
Traditional wireless communication systems are usually designed for a specific standard, such as GSM (Global System for Mobile Communications), Wideband Code Division Multiple Access (W-CDMA), Wi-Fi® (registered trademark of Wi-Fi Alliance of Austin, Tex.), LTE (Long Term Evolution), just to name a few. Current demand for the convergence of wireless services, so that users can access different standards from the same wireless device, is driving the development of multi-standard and multi-band transceivers, which are capable of transmitting/receiving radio signals in the entire wireless communication spectrum (most are in a frequency range of from 300 MHz to 3.6 GHz).
The multi-band/multi-standard requirement drives the need for wideband RF transceivers and power amplifiers (PAs). However, wideband PAs often suffer from lower power efficiency than narrowband PAs, and power efficiency is essential for power-constraint, compact mobile devices.